arch/arm64/include/asm/cmpxchg.h

   1 /*
   2  * Based on arch/arm/include/asm/cmpxchg.h
   3  *
   4  * Copyright (C) 2012 ARM Ltd.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18 #ifndef __ASM_CMPXCHG_H
  19 #define __ASM_CMPXCHG_H
  20
  21 #include <linux/bug.h>
  22
  23 #include <asm/atomic.h>
  24 #include <asm/barrier.h>
  25 #include <asm/lse.h>
  26
  27 /*
  28  * We need separate acquire parameters for ll/sc and lse, since the full
  29  * barrier case is generated as release+dmb for the former and
  30  * acquire+release for the latter.
  31  */
  32 #define __XCHG_CASE(w, sz, name, mb, nop_lse, acq, acq_lse, rel, cl)    \
  33 static inline unsigned long __xchg_case_##name(unsigned long x,         \
  34                                                volatile void *ptr)      \
  35 {                                                                       \
  36         unsigned long ret, tmp;                                         \
  37                                                                         \
  38         asm volatile(ARM64_LSE_ATOMIC_INSN(                             \
  39         /* LL/SC */                                                     \
  40         "       prfm    pstl1strm, %2\n"                                \
  41         "1:     ld" #acq "xr" #sz "\t%" #w "0, %2\n"                    \
  42         "       st" #rel "xr" #sz "\t%w1, %" #w "3, %2\n"               \
  43         "       cbnz    %w1, 1b\n"                                      \
  44         "       " #mb,                                                  \
  45         /* LSE atomics */                                               \
  46         "       nop\n"                                                  \
  47         "       nop\n"                                                  \
  48         "       swp" #acq_lse #rel #sz "\t%" #w "3, %" #w "0, %2\n"     \
  49         "       nop\n"                                                  \
  50         "       " #nop_lse)                                             \
  51         : "=&r" (ret), "=&r" (tmp), "+Q" (*(u8 *)ptr)                   \
  52         : "r" (x)                                                       \
  53         : cl);                                                          \
  54                                                                         \
  55         return ret;                                                     \
  56 }
  57
  58 __XCHG_CASE(w, b,     1,        ,    ,  ,  ,  ,         )
  59 __XCHG_CASE(w, h,     2,        ,    ,  ,  ,  ,         )
  60 __XCHG_CASE(w,  ,     4,        ,    ,  ,  ,  ,         )
  61 __XCHG_CASE( ,  ,     8,        ,    ,  ,  ,  ,         )
  62 __XCHG_CASE(w, b, acq_1,        ,    , a, a,  , "memory")
  63 __XCHG_CASE(w, h, acq_2,        ,    , a, a,  , "memory")
  64 __XCHG_CASE(w,  , acq_4,        ,    , a, a,  , "memory")
  65 __XCHG_CASE( ,  , acq_8,        ,    , a, a,  , "memory")
  66 __XCHG_CASE(w, b, rel_1,        ,    ,  ,  , l, "memory")
  67 __XCHG_CASE(w, h, rel_2,        ,    ,  ,  , l, "memory")
  68 __XCHG_CASE(w,  , rel_4,        ,    ,  ,  , l, "memory")
  69 __XCHG_CASE( ,  , rel_8,        ,    ,  ,  , l, "memory")
  70 __XCHG_CASE(w, b,  mb_1, dmb ish, nop,  , a, l, "memory")
  71 __XCHG_CASE(w, h,  mb_2, dmb ish, nop,  , a, l, "memory")
  72 __XCHG_CASE(w,  ,  mb_4, dmb ish, nop,  , a, l, "memory")
  73 __XCHG_CASE( ,  ,  mb_8, dmb ish, nop,  , a, l, "memory")
  74
  75 #undef __XCHG_CASE
  76
  77 #define __XCHG_GEN(sfx)                                                 \
  78 static inline unsigned long __xchg##sfx(unsigned long x,                \
  79                                         volatile void *ptr,             \
  80                                         int size)                       \
  81 {                                                                       \
  82         switch (size) {                                                 \
  83         case 1:                                                         \
  84                 return __xchg_case##sfx##_1(x, ptr);                    \
  85         case 2:                                                         \
  86                 return __xchg_case##sfx##_2(x, ptr);                    \
  87         case 4:                                                         \
  88                 return __xchg_case##sfx##_4(x, ptr);                    \
  89         case 8:                                                         \
  90                 return __xchg_case##sfx##_8(x, ptr);                    \
  91         default:                                                        \
  92                 BUILD_BUG();                                            \
  93         }                                                               \
  94                                                                         \
  95         unreachable();                                                  \
  96 }
  97
  98 __XCHG_GEN()
  99 __XCHG_GEN(_acq)
 100 __XCHG_GEN(_rel)
 101 __XCHG_GEN(_mb)
 102
 103 #undef __XCHG_GEN
 104
 105 #define __xchg_wrapper(sfx, ptr, x)                                     \
 106 ({                                                                      \
 107         __typeof__(*(ptr)) __ret;                                       \
 108         __ret = (__typeof__(*(ptr)))                                    \
 109                 __xchg##sfx((unsigned long)(x), (ptr), sizeof(*(ptr))); \
 110         __ret;                                                          \
 111 })
 112
 113 /* xchg */
 114 #define xchg_relaxed(...)       __xchg_wrapper(    , __VA_ARGS__)
 115 #define xchg_acquire(...)       __xchg_wrapper(_acq, __VA_ARGS__)
 116 #define xchg_release(...)       __xchg_wrapper(_rel, __VA_ARGS__)
 117 #define xchg(...)               __xchg_wrapper( _mb, __VA_ARGS__)
 118
 119 #define __CMPXCHG_GEN(sfx)                                              \
 120 static inline unsigned long __cmpxchg##sfx(volatile void *ptr,          \
 121                                            unsigned long old,           \
 122                                            unsigned long new,           \
 123                                            int size)                    \
 124 {                                                                       \
 125         switch (size) {                                                 \
 126         case 1:                                                         \
 127                 return __cmpxchg_case##sfx##_1(ptr, (u8)old, new);      \
 128         case 2:                                                         \
 129                 return __cmpxchg_case##sfx##_2(ptr, (u16)old, new);     \
 130         case 4:                                                         \
 131                 return __cmpxchg_case##sfx##_4(ptr, old, new);          \
 132         case 8:                                                         \
 133                 return __cmpxchg_case##sfx##_8(ptr, old, new);          \
 134         default:                                                        \
 135                 BUILD_BUG();                                            \
 136         }                                                               \
 137                                                                         \
 138         unreachable();                                                  \
 139 }
 140
 141 __CMPXCHG_GEN()
 142 __CMPXCHG_GEN(_acq)
 143 __CMPXCHG_GEN(_rel)
 144 __CMPXCHG_GEN(_mb)
 145
 146 #undef __CMPXCHG_GEN
 147
 148 #define __cmpxchg_wrapper(sfx, ptr, o, n)                               \
 149 ({                                                                      \
 150         __typeof__(*(ptr)) __ret;                                       \
 151         __ret = (__typeof__(*(ptr)))                                    \
 152                 __cmpxchg##sfx((ptr), (unsigned long)(o),               \
 153                                 (unsigned long)(n), sizeof(*(ptr)));    \
 154         __ret;                                                          \
 155 })
 156
 157 /* cmpxchg */
 158 #define cmpxchg_relaxed(...)    __cmpxchg_wrapper(    , __VA_ARGS__)
 159 #define cmpxchg_acquire(...)    __cmpxchg_wrapper(_acq, __VA_ARGS__)
 160 #define cmpxchg_release(...)    __cmpxchg_wrapper(_rel, __VA_ARGS__)
 161 #define cmpxchg(...)            __cmpxchg_wrapper( _mb, __VA_ARGS__)
 162 #define cmpxchg_local           cmpxchg_relaxed
 163
 164 /* cmpxchg64 */
 165 #define cmpxchg64_relaxed       cmpxchg_relaxed
 166 #define cmpxchg64_acquire       cmpxchg_acquire
 167 #define cmpxchg64_release       cmpxchg_release
 168 #define cmpxchg64               cmpxchg
 169 #define cmpxchg64_local         cmpxchg_local
 170
 171 /* cmpxchg_double */
 172 #define system_has_cmpxchg_double()     1
 173
 174 #define __cmpxchg_double_check(ptr1, ptr2)                                      \
 175 ({                                                                              \
 176         if (sizeof(*(ptr1)) != 8)                                               \
 177                 BUILD_BUG();                                                    \
 178         VM_BUG_ON((unsigned long *)(ptr2) - (unsigned long *)(ptr1) != 1);      \
 179 })
 180
 181 #define cmpxchg_double(ptr1, ptr2, o1, o2, n1, n2) \
 182 ({\
 183         int __ret;\
 184         __cmpxchg_double_check(ptr1, ptr2); \
 185         __ret = !__cmpxchg_double_mb((unsigned long)(o1), (unsigned long)(o2), \
 186                                      (unsigned long)(n1), (unsigned long)(n2), \
 187                                      ptr1); \
 188         __ret; \
 189 })
 190
 191 #define cmpxchg_double_local(ptr1, ptr2, o1, o2, n1, n2) \
 192 ({\
 193         int __ret;\
 194         __cmpxchg_double_check(ptr1, ptr2); \
 195         __ret = !__cmpxchg_double((unsigned long)(o1), (unsigned long)(o2), \
 196                                   (unsigned long)(n1), (unsigned long)(n2), \
 197                                   ptr1); \
 198         __ret; \
 199 })
 200
 201 /* this_cpu_cmpxchg */
 202 #define _protect_cmpxchg_local(pcp, o, n)                       \
 203 ({                                                              \
 204         typeof(*raw_cpu_ptr(&(pcp))) __ret;                     \
 205         preempt_disable();                                      \
 206         __ret = cmpxchg_local(raw_cpu_ptr(&(pcp)), o, n);       \
 207         preempt_enable();                                       \
 208         __ret;                                                  \
 209 })
 210
 211 #define this_cpu_cmpxchg_1(ptr, o, n) _protect_cmpxchg_local(ptr, o, n)
 212 #define this_cpu_cmpxchg_2(ptr, o, n) _protect_cmpxchg_local(ptr, o, n)
 213 #define this_cpu_cmpxchg_4(ptr, o, n) _protect_cmpxchg_local(ptr, o, n)
 214 #define this_cpu_cmpxchg_8(ptr, o, n) _protect_cmpxchg_local(ptr, o, n)
 215
 216 #define this_cpu_cmpxchg_double_8(ptr1, ptr2, o1, o2, n1, n2)           \
 217 ({                                                                      \
 218         int __ret;                                                      \
 219         preempt_disable();                                              \
 220         __ret = cmpxchg_double_local(   raw_cpu_ptr(&(ptr1)),           \
 221                                         raw_cpu_ptr(&(ptr2)),           \
 222                                         o1, o2, n1, n2);                \
 223         preempt_enable();                                               \
 224         __ret;                                                          \
 225 })
 226
 227 #define __CMPWAIT_CASE(w, sz, name)                                     \
 228 static inline void __cmpwait_case_##name(volatile void *ptr,            \
 229                                          unsigned long val)             \
 230 {                                                                       \
 231         unsigned long tmp;                                              \
 232                                                                         \
 233         asm volatile(                                                   \
 234         "       ldxr" #sz "\t%" #w "[tmp], %[v]\n"              \
 235         "       eor     %" #w "[tmp], %" #w "[tmp], %" #w "[val]\n"     \
 236         "       cbnz    %" #w "[tmp], 1f\n"                             \
 237         "       wfe\n"                                                  \
 238         "1:"                                                            \
 239         : [tmp] "=&r" (tmp), [v] "+Q" (*(unsigned long *)ptr)           \
 240         : [val] "r" (val));                                             \
 241 }
 242
 243 __CMPWAIT_CASE(w, b, 1);
 244 __CMPWAIT_CASE(w, h, 2);
 245 __CMPWAIT_CASE(w,  , 4);
 246 __CMPWAIT_CASE( ,  , 8);
 247
 248 #undef __CMPWAIT_CASE
 249
 250 #define __CMPWAIT_GEN(sfx)                                              \
 251 static inline void __cmpwait##sfx(volatile void *ptr,                   \
 252                                   unsigned long val,                    \
 253                                   int size)                             \
 254 {                                                                       \
 255         switch (size) {                                                 \
 256         case 1:                                                         \
 257                 return __cmpwait_case##sfx##_1(ptr, (u8)val);           \
 258         case 2:                                                         \
 259                 return __cmpwait_case##sfx##_2(ptr, (u16)val);          \
 260         case 4:                                                         \
 261                 return __cmpwait_case##sfx##_4(ptr, val);               \
 262         case 8:                                                         \
 263                 return __cmpwait_case##sfx##_8(ptr, val);               \
 264         default:                                                        \
 265                 BUILD_BUG();                                            \
 266         }                                                               \
 267                                                                         \
 268         unreachable();                                                  \
 269 }
 270
 271 __CMPWAIT_GEN()
 272
 273 #undef __CMPWAIT_GEN
 274
 275 #define __cmpwait_relaxed(ptr, val) \
 276         __cmpwait((ptr), (unsigned long)(val), sizeof(*(ptr)))
 277
 278 #endif  /* __ASM_CMPXCHG_H */